JP2002254233A - Flat drag tip for face milling cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To nicely finish a foundry material such as aluminum base alloy or cast iron, using a flat drag tip for a face milling cutter made of an ultra-high pressure sintered compact or coated extra-abrasive grains. SOLUTION: An increase in cutting resistance is restrained by forming a groove 7 so that a front cutting edge is shaped as comb teeth. The cutting face of the front cutting edge is also formed so that a rake angle θ in the axial direction when the flat drag tip 1 is mounted on the face milling cutter 11 becomes a negative rake angle of 20 deg. to 60 deg.. As a result, a plastic flow generated on the machining surface prevents exposure of a blow hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Sarai blade tip for face milling, in which at least a front cutting edge is formed by an ultra-high pressure sintered body or a super abrasive coating.

[0002]

2. Description of the Related Art Finishing of cast parts such as aluminum alloy and cast iron includes cutting and grinding. Grinding generally provides better surface finish than cutting, and in addition to high toughness, plastic flow occurs on the machined surface, which prevents the exposure of latent cavities in the material. . However, because of high grinding resistance, high rigidity and high precision machine tools are required,
In addition, the cutting efficiency is inferior because there is a problem such as clogging or abrasive grains falling off due to the limitation of the cut amount.

[0003] On the other hand, cutting with a face mill has less problems as described above than grinding, but has a problem in terms of the roughness of the machined surface. As one of means for improving the problem of the machined surface, there is a Sarai blade tip in which the front cutting edge is an arc or a straight cutting edge having a large radius. The method of mounting the Sarai blade tip in all the mounting grooves of the face milling machine,
There is a method that is mounted in combination with a normal blade insert that performs rough machining so that it can cope with deep cutting. More recently, as a method similar to grinding, a method in which a saray blade tip is formed of a sintered body or a coated body of superabrasive grains has been put into practical use.

[0004]

In the cutting of aluminum alloys and cast irons having high toughness, the adhesion of chips to the cutting edges is apt to occur. Cutting edge chipping that occurs as the kimono falls off deteriorates the finished surface roughness. Cubic boron nitride and diamond have the property that chips do not easily adhere to the cutting edge, and because of their excellent wear resistance,
Good finished surface roughness can be obtained. However, since the sharpness is good, plastic flow on the processed surface is unlikely to occur, and rather, fine voids in the material are exposed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to obtain a good finished surface by cutting, and the first aspect is that at least the front cutting edge is coated with an ultrahigh-pressure sintered body or superabrasive grains. In a salary blade tip for a face milling formed by a body, the front cutting edge is formed in a comb shape by a groove-shaped portion attached to the front cutting edge, The rake face of the front cutting edge
The sali-blade tip is formed so that the axial rake angle θ when attached to the face mill is a negative rake angle of 20 ° to 60 °.

The purpose of forming the front cutting edge in the shape of a comb tooth is to reduce the cutting resistance in the axial direction of the Sarai blade, particularly the face mill, caused by the long contact length with the work material. is there. This is more effective in combination with making the axial rake angle θ a negative rake angle. The reason for setting the axial rake angle θ to be a negative rake angle is to cause a plastic flow on a processed surface to bury a small porosity. Further, the angle θ adopts a negative angle of 20 ° to 60 ° in accordance with the cutting action performed by one abrasive grain of the grindstone. That is, the angle at which plastic flow occurs is set to a negative angle of 20 ° or more, and the angle at which cutting resistance is not excessively large is set to a negative angle of 60 ° or less.

A third aspect of the present invention is that the front cutting blade is provided on an outer peripheral side when the front milling machine is mounted,
It is characterized by comprising parallel cutting blades arranged on the inner peripheral side and parallel to the front. In other words, the inclined cutting edge that is inclined in the feed direction of the face mill reduces the biting impact on the workpiece in the cutting direction, and at the same time, if the inclined cutting edge is long, the part also has comb teeth. , And receives the same cutting resistance reducing action as described above.

A fourth aspect of the present invention is characterized in that a plurality of the front cutting blades are arranged in a thickness direction of the chip, and a fifth aspect is a plurality of the front cutting edges arranged in a thickness direction of the chip. The cutting blades are arranged out of phase. In these methods, the arrangement of the cutting blades is made closer to the grindstone, and is employed as a means for obtaining a finished surface roughness close to the ground surface while compensating for the disadvantages of the grindstone.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a front view of a Sarai blade tip 1 according to the present invention, in which a notch step 2 provided on one side of a square flat chip body is shown.
Then, a chip piece 3 made of an ultra-high pressure sintered body such as cubic boron nitride or diamond or a coated body of super abrasive grains is brazed and joined. The long side of the chip piece 3 becomes the front cutting edge 4.

FIG. 2 is an enlarged view of the chip piece 3. The front cutting edge 4 includes an inclined cutting edge 5 arranged on the outer peripheral side when the front milling machine is mounted, and a parallel cutting edge 6 arranged on the inner peripheral side and parallel to the front. The inclination angle of the inclined cutting blade 5 with respect to the front surface is usually set to a gentle inclination angle of 20 ° or less in view of the relationship with the cut amount of the Sarai blade.
From the inclined cutting edge 5 to the parallel cutting edge 6, grooves 7 in the vertical direction are provided at a certain interval in the parallel cutting edge 6 to form comb teeth, so that the front cutting edge 4 is an intermittent cutting edge. Has become.

In the present invention, the axial rake angle θ is 2
In order to have a negative rake angle between 0 ° and 60 °,
The chip piece 3 is chamfered at an angle α with respect to the upper surface 8 to form a substantially rake face 9 of the parallel cutting edge 6.
For example, if the axial rake angle of the tip seat on which the Sarai blade tip 1 is mounted is 0 °, the chamfer angle α = the axial rake angle θ. In addition, in the throw-away type face mill 10 shown in FIG. 3, if the axial rake angle of the tip seat is a positive angle, the chamfer angle α is set to be larger than the axial rake angle θ by that angle. And
Since the chamfered surface is a substantial rake face 9, its width is preferably large, and at least の of the cut
As described above, the size may exceed the cut. The increase in cutting resistance caused by setting the axial rake angle θ to a large negative angle is reduced by using a comb tooth cutting edge.

In a face mill as shown in FIG.
The sarai blade tip 1 can be used in combination with a normal blade tip 11 for rough machining. However, the front cutting edge 4
However, depending on the feed conditions of the face mill 10, residual cutting due to the groove 7 may occur. In such a case, two or more Sarai blade tips 1 are mounted.

FIG. 4 shows the positional relationship between the cutting edge of the Sarai blade tip 1 and the ordinary blade tip 11 on the rotation locus.
The sarai blade tip 1 is retracted to the outer peripheral side from the ordinary blade tip 11 and slightly protrudes to the front side. The notch on the Sarai blade tip 1 corresponds to this protrusion amount, and is 0.5 m
In general, the cut is about m or less.

FIG. 5 shows the practical results of the product of the present invention and other conventional products, and compares the processed surfaces of aluminum alloys. (A) is a conventional diamond sintered body chip,
In other words, it has one continuous front cutting edge and shows a cutting surface with a tip mounted at a regular angle of rake angle of 5 °,
In some cases, the finished surface has a good surface roughness due to good sharpness, but the cavities are exposed due to good sharpness, which is rejected depending on the processing quality required for the product. (C) shows the surface ground by a diamond whetstone, in which no cavities were exposed and the finished surface was satisfactory. However, as described above, the grinding had problems of clogging and processing efficiency. There is. (B) shows a machined surface when the chip of the present invention is used. The enlarged photograph shows a scratch-like seemingly rough finished surface, but the 10-point average roughness Rz is 1.1 μm and the quality is high. The maximum roughness is not more than 1.5 μm because the plastic flow of the work material caused by the negative rake angle prevents the exposure of the cavities (data not shown). It has become.

FIG. 6 shows another embodiment of the present invention, and the shape of the front cutting edge 4 is different from that of FIG. That is, since the front end of the intermittent front cutting edge 4 is formed in an arc shape, and the contact length with the work material is reduced, the cutting resistance is further reduced. On the other hand, the roughness of the finished surface tends to decrease.
It is advisable to use with a larger number of mounted.

FIG. 7 shows another embodiment of the present invention, in which a plurality of front cutting blades 4 are arranged in the thickness direction of one chip 3.
Is arranged. Since the front end of the front cutting edge 4 is arranged out of phase by providing the groove 7 at an angle,
There is no need to worry about leaving uncut parts. Since the mounting of a plurality of Sarai blade tips 3 can be handled by a single tip, the same effect as a multi-blade Sarai blade can be achieved without reducing the number of ordinary blade tips 11. The burden on the ordinary blade tip 11 can be reduced.

[0017]

The face milling tip of the present invention is
Since the front cutting edge is formed in a comb tooth shape, it is possible to suppress an increase in cutting resistance, particularly in the axial direction, of the Sarai blade tip. Since cutting resistance is suppressed, stable cutting is possible even if the axial rake angle θ is set to a negative angle, and by setting the axial rake angle θ to a negative angle of 20 ° to 60 °, aluminum alloy etc. In this case, plastic flow is caused on the processed surface to prevent the exposure of the cavities, so that a uniform finished surface can be obtained on the entire surface. Since the comb-shaped inclined cutting edge is formed at the outer peripheral position of the front cutting edge, biting impact during cutting is reduced. In addition, by arranging a plurality of front cutting blades in the thickness direction of one Sarai blade tip and further displacing the phases, cutting in a shape closer to the grindstone will be performed, It is possible to use the ordinary blade tip together without reducing the number of ordinary blade tips.

[Brief description of the drawings]

FIG. 1 is a front view of a salari blade tip according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a salai blade portion of FIG. 1 and (a).
Is a front view, and (b) is a side view.

FIGS. 3A and 3B show one form of a front milling cutter to which a salari blade tip of the present invention is mounted, wherein FIG. 3A is an upper side view and FIG. 3B is a front view.

FIG. 4 is a view for explaining a positional relationship of a cutting edge between a normal blade tip and a salai blade tip.

FIG. 5 is a comparison diagram for explaining a difference in a machined surface due to a difference in various tools.

FIGS. 6A and 6B are enlarged views of a salary blade portion according to another embodiment of the present invention, wherein FIG. 6A is a front view and FIG. 6B is a side view.

FIGS. 7A and 7B are enlarged views of a salary blade portion according to another embodiment of the present invention, wherein FIG. 7A is a front view, FIG.
(C) is a bottom view.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Sarai blade tip 3 Tip piece 4 Front cutting edge 5 Inclined cutting edge 6 Parallel cutting edge 7 Groove 9 Rake face θ Rake angle in axial direction

Claims (5)

[Claims] 1. A salari blade tip for a face mill, wherein at least the front cutting edge is formed of an ultra-high pressure sintered body or a superabrasive coating, wherein the front face is formed by a groove-shaped portion attached to the front cutting edge. A Sarai blade tip for face milling, wherein the cutting blade is formed in a comb shape. 2. The rake face of the front cutting edge is formed such that the axial rake angle θ when the Sarai blade tip is mounted on a face mill is a negative rake angle of 20 ° to 60 °. The salary blade tip for a face mill according to claim 1, wherein 3. An inclined cutting edge arranged on an outer peripheral side when a front milling machine is mounted, and a parallel cutting edge arranged on an inner peripheral side thereof so as to be parallel to the front surface. 3. The saray blade tip for a face milling machine according to claim 1, wherein the tip is constituted by: 4. The Sarai blade tip for a face mill according to claim 1, wherein a plurality of the front cutting blades are arranged in a thickness direction of the chip. 5. The Sarai blade tip for a face mill according to claim 4, wherein the plurality of the front cutting blades arranged in the thickness direction of the chip are arranged out of phase.